Description of the Pest
Grasshoppers can be occasional pests of corn. In late summer and fall, grasshopper eggs are laid in grassy foothills, on ditchbanks, along roadsides and fence rows, in pasture areas, and in alfalfa fields. Eggs hatch in spring and young nymphs feed on nearby plants. When wild grasses and other plants become dry, grasshoppers migrate to irrigated croplands.
Damage
Grasshoppers feed on foliage, most often on the edges of fields near pasture areas or roadsides. They seldom cause economically significant injury.
Management
Topical treatments are most effective; treating field borders may be adequate.
| Common name | Amount/Acre** | REI‡ | PHI‡ | |
|---|---|---|---|---|
| (Example trade name) | (hours) | (days) | ||
| Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Always read the label of the product being used. | ||||
| A. | CARBARYL* | |||
| (Sevin) 80S, XLR Plus | 10–24 oz | 12 | Sweet corn: 2 Forage: 14 Grain or fodder: 48 |
|
| MODE OF ACTION GROUP NUMBER1: 1A | ||||
| COMMENTS: Ground or air application. | ||||
| B. | MALATHION 8E | 1 pt | 12 | Harvest or forage: 5 |
| MODE OF ACTION GROUP NUMBER1: 1B | ||||
| COMMENTS: Limited residual effectiveness. | ||||
| ** | Mix with sufficient water to obtain full coverage. |
| ‡ | Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest. |
| * | Permit required from county agricultural commissioner for purchase or use. |
| 1 | Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). |